Speed indicator for a bicycle

Abstract: A speed indicator includes a stationary member (5) fixed to a handlebar of a bicycle, a takeup element (7) supported by the stationary member to be rotatable about a first axis (X) for taking up a control cable, a shift lever (4) for rotating the takeup element, and a pointer (9) pivotable about a second axis (P) fixed to the stationary member. The pointer overlaps the takeup element as viewed in a direction along the first axis. The speed indicator further includes an indicating section for cooperating with the pointer for indicating a speed stage selected by operation of the shift lever. The takeup element has a projection (12) engaged with a slot formed in the pointer for causing the pointer to pivot in response to rotation of the takeup element.

Description: BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a speed indicator for a shifting device of a bicycle having a plurality of speed stages. DESCRIPTION OF THE RELATED ART A conventional shifting device includes a disk forming a takeup element for winding a speed control cable, and this disk has an arrow acting as a pointer. When a shifting operation is carried out, the arrow is swung to indicate a selected speed stage. In such a conventional shifting device, the pointer is attached to the takeup element to be operable therewith. When, for example, the shifting device is reduced in size, the takeup element has a reduced outer configuration. Then, even when the takeup element rotates from a minimum speed stage to a maximum speed stage, the pointer is operable only through a very short stroke. This results in an inconvenience that speed indicating marks must he arranged at slight intervals along a moving track of the pointer. Further, in certain types of shifting device, the takeup element must have different angles of rotation, such that the takeup element is rotatable through different angles for shifting from a first speed stage to a second speed stage and for shifting from the second speed stage to a third speed stage. In such a case, the pointer also is movable through different angles, which results in an inconvenience of having to arrange the speed indicating marks at varied intervals along the moving track of the pointer. In US-PS 3,633,437 an indicating apparatus for a change gear mechanism of a bicycle in accordance with the preamble of claim 1 is shown having a driven means being rotatable for rotating a wire connected with the change gear mechanism. The control device further comprises a disk plate marked with an arrow for indicating the selected gear. The arrow can be seen through an aperture. This control device results in the drawback that sand and dust can be introduced through the aperture and reduce the service life of the control device. SUMMARY OF THE INVENTION An object of the present invention is to provide a speed indicator having a simple construction to indicate rotational displacements of a takeup element in an amplified manner, while allowing a reduction in size of the device. It is another object of the invention to provide a speed indicator which enables speed indicating marks to he arranged equidistantly as necessary, even if a takeup element is rotatable through different angles for establishing different speed stages. The above objects are fulfilled by an indicating apparatus in accordance with claim 1. In the above construction, the first indicating means such as a pointer is interlocked to the takeup element, but is pivotally supported by an axis different from a rotational axis of the takeup element. Moreover, the first indicating device is in an overlapping relationship with the takeup element. Consequently, rotational displacements of the takeup element may be amplified without enlarging the entire apparatus. Further and other objects, features and effects of the invention will become more apparent from the following more detailed description of the embodiments of the invention taken with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a shifting device having a speed indicator according to the present invention; Fig. 2 is a sectional view taken along a pivotal axis of control levers of the shifting device of Fig. 1; and Fig. 3 is a sectional view of a principal portion of the speed indicator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An indicating apparatus according to the present invention will be described hereinafter with reference to the drawings. As shown in Fig. 1, a lever bracket 2 pivotably supports a brake lever 3. The lever bracket 2 also supports a shifting device including a shift lever 4 and a speed indicator A. The shifting device will particularly be described with reference to Fig. 2. A stationary member 5 is fixed to a support portion 2a of the lever bracket 2. The stationary member 5 supports a takeup element 7 to be rotatable on a support shaft 6 for taking up an inner wire 8a of a control cable 8. The shift lever 4 (Fig. 3) also is attached to the support shaft 6 to be pivotable about an axis X acting as a first axis. In this embodiment, as seen from Fig. 3, the shift lever 4 has a Y-shaped overall configuration including a first control portion 4a and a second control portion 4b. The takeup element 7 is biased in a an unwinding direction by a biasing spring included in a derailleur not shown. When the rider operates the shift lever 4 by means of the first control portion 4a or second control portion 4b, the takeup element 7 is rotated through a control mechanism, not shown, to wind or unwind the inner wire 8a of the control cable 8. As shown in Fig. 3, the shift lever 4 is pivotable from home position N to a first shift position U to rotate the takeup element 7 counterclockwise in Fig. 3. As a result, the inner wire 8a is wound on the takeup element 7 to effect a shift by one stage. When the shift lever 4 is released after this shifting operation, the shift lever 4 returns to the home position N under the biasing force of a return spring. This operation is repeated to effect a further shift. For unwinding the wire, the shift lever 4 is operated to a second shift position D. As a result, the takeup element 7 is rotated clockwise in Fig 3, allowing the inner wire 8a to be drawn from the takeup element 7. In this case also, the operation of the shift lever 4 to the second shift position D effects a shift by one stage. After this operation, the shift lever 4 may be returned to the home position N under a biasing force. To enable the foregoing functions, the shifting device in this embodiment includes a feed pawl, a return pawl and a stopper pawl of the ratchet type (none of these pawls heing shown in the drawings). Specifically, when the shift lever 4 is operated from home position N to first shift position U, the feed pawl engages the takeup element 7 to transmit an operating force to rotate the takeup element 7 to a position corresponding to a new speed stage. During the pivotal movement of the shift lever 4 from home position N to first shift position U, the stopper pawl is automatically held in an inoperative position by the control mechanism. Once the shift lever 4 reaches the first shift position U, placing the takeup element 7 in the position corresponding to the new speed stage, the control mechanism actuates the stopper pawl to maintain the takeup element 7 in that new speed stage position. When the shift lever 4 returns from first shift position U to home position N under the biasing force, the feed pawl is automatically disengaged from the takeup element 7. Then the takeup element 7 is retained in the new speed stage position by the stopper pawl. Similarly, when the shift lever 4 is operated from home position N to second shift position D, the return pawl engages the takeup element 7 to transmit an operating force to rotate the takeup element 7 to a position corresponding to a new speed stage. During the pivotal movement of the shift lever 4 from home position N to second shift position D, the stopper pawl is automatically held in the inoperative position by the control mechanism. Once the shift lever 4 reaches the second shift position D, placing the takeup element 7 in the position corresponding to the new speed stage, the control mechanism actuates the stopper pawl to maintain the takeup element 7 in that new speed stage position. When the shift lever 4 returns from second shift position D to home position N under the biasing force, the return pawl is automatically disengaged from the takeup element 7. Then the takeup element 7 is retained in the new speed stage position by the stopper pawl. The speed indicator A according to the present invention will he described next. As shown in Fig. 2, the stationary member 5 has an axis P fixed thereto to act as a second axis extending substantially parallel to the rotational axis X of the takeup element 7. A pointer 9 is pivotably supported by this axis P to act as a first indicating device. The stationary member 5 further supports a housing 10 for accommodating the takeup element 7, the control mechanism and so on. The housing 10 includes a transparent plate 11 to render the pointer 9 visible from outside the housing 10, and a speed scale panel 10a acting as a second indicating device to indicate speed stages in cooperation with the pointer 9. As viewed in a direction along the axis X, the speed scale panel 10a is disposed in a position substantially opposite to the axis P across the takeup element 7. As shown in Figs. 2 and 3, a projection 12 is formed on an upper surface in a peripheral region of the takeup element 7. The projection 12 has a free end thereof extending through a slot 9b formed in the pointer 9. As shown in Fig. 3, the slot 9b extends substantially longitudinally of the pointer 9 between the pivotal axis P and a distal end portion 9a of the pointer 9. As viewed in a direction perpendicular to the axis X (Fig. 2), the pointer 9 includes a horizontal portion 9c extending substantially horizontally from the pivotal axis P, an intermediate portion 9d sloping generally downward from the horizontal portion 9c and then extending horizontally, and the distal end portion 9a extending substantially vertically from the intermediate portion 9d. Thus, when the takeup element 7 is rotated in a shifting operation, the projection 12 extending through the slot 9b pushes the pointer 9 while sliding relative thereto. As a result, the pointer 9 pivots about the axis P, with the distal end portion 9a of the pointer 9 moving along an inner surface of the transparent plate 11. When the takeup element 7 stops rotating, the pointer 9 stops at a selected indicating position. At this time, the distal end portion 9a of the pointer 9 points at one of a plurality of marks or numerals 13 shown on the speed scale panel 10a, which numeral corresponds to a speed stage for which the takeup element 7 has been rotated and stopped. As shown in Fig. 3, the pivotal axis P of the pointer 9 is located adjacent a peripheral region of the takeup element 7 and substantially opposite to the distal end portion 9a and transparent plate 11 across the rotational axis X. That is, as viewed in a direction along the rotational axis X, the pointer 9 is disposed in a constantly overlapping relationship with the takeup element 7. In this embodiment, seven speed stages are provided. When the takeup element 7 lies in a position corresponding to the fourth speed stage which is the middle stage among the seven stages, a straight line extending from the axis P through the projection 12 to the distal end portion 9a is offset from the rotational axis X of the takeup element 7. In Fig. 3, the distal end portion 9a points at the fourth speed stage. In this state, the pointer 9 does not lie on the rotational axis X. That is, the pivotal axis P and projection 12 are arranged asymmetrically about the axis X. With this arrangement, even if the takeup element 7 has unequal angles of rotation, e.g. larger angles for low speed stages than for high speed stages, the distal end portion 9a of the pointer 9 is movable through substantially the same intervals to facilitate visual presentation of the speed stages. For enabling the distal end portion 9a to move through substantially the same intervals as above, it is necessary to take two points into account. One of these points is a relationship between a distance by which the takeup element 7 rotates to shift from one speed stage to a next adjacent speed stage, and an angle by which the pointer 9 pivots in accordance with that distance. The other point is a ratio between a distance from the pivotal axis P to the projection 12, and a distance from the projection 12 to the distal end portion 9a. The larger this ratio is, the movement of the distal end portion 9a is amplified to the greater extent even if the pointer 9 pivots through a small angle about the pivotal axis P. By suitably balancing the two relationships, the distal end portion 9a is allowed to move through substantially the same intervals. Other embodiments of the present invention will be described next. In the foregoing embodiment, the pivotal axis P of the pointer 9 extends substantially parallel to the rotational axis X of the takeup element 7. Such a construction allows the entire pointer 9 to be disposed close to the takeup element 7, and hence an advantage of enabling the shifting device to be compact. However, it is not essential for the pivotal axis P of the pointer 9 to he parallel to the rotational axis X of the takeup element 7. In the foregoing embodiment, the pointer 9 is operable in response to the takeup element 7. It is possible, however, to fix the pointer to a stationary member, with the speed scale panel interlocked to the takeup element. In the foregoing embodiment, the projection 12 is formed on the takeup element 7. Instead, the projection may be formed on the pointer, with the takeup element defining a bore for engaging the projection. The slot for engaging the projection may be curved instead of being linear. The nonlinear slot should preferably be shaped to enable the indicating device to move substantially constant amounts even when the takeup element rotates through different angles to establish different speed stages. The present invention is applicable also to other types of shifting devices than the described shifting device in which the shift lever is returned to home position after each shifting operation. Such other shifting devices include one in which a shift lever is connected to a takeup element such that the shift lever and takeup element may be stopped together at a selected speed position.

Claims: An indicating apparatus for a shift controller of a bicycle having a plurality of speed stages comprising: a stationary member (5) fixed to a handle bar (1) of said bicycle; a take-up element (7) supported by said stationary member (5) to be rotatable about a first axis for taking up a control cable; a shift lever (4) for rotating said take-up element (7); a first indicating means (9) rotating with said take-up element (7); second indicating means (11, 13) fixed to said stationary member (5) for cooperating with said first indicating means (9) to indicate one of said speed stages selected by operation of said shift lever (4); characterized in that said first indicating means (9) is pivotable about a second axis fixed to said stationary member (5), said indicating means (9) overlapping said take-up element (7) as viewed in a direction along said first axis; interlock means (12, 9b) for interlocking said first indicating means (9) and said take-up element (7) to enable said first indicating means (9) to pivot in response to rotation of said take-up element (7) whereby said second indicating means (11, 13) is disposed substantially opposite to said second axis as viewed in the direction along said first axis. An indicating apparatus as defined in claim 1, characterized in that said first indicating means is a pointer (9). An indicating apparatus as defined in claim 2, characterized in that said second indicating means (11, 13) is an indicating section having marks corresponding to said plurality of speed stages. An indicating apparatus as defined in claim 1, characterized in that said first axis and said second axis extend substantially parallel to each other. An indicating apparatus as defined in claim 1, characterized in that when said first indicating means (9) lies in a position for indicating a middle one of said pluralilty of speed stages, a straight line extending between said second axis and said interlock means (12, 9b) is substantially displaced from said first axis. An indicating apparatus as defined in claim 2, characterized in that said interlock means (12, 9b) includes a projection (12) fixedly formed on said take-up element (7), and a bore (9b) formed in said pointer (9) for receiving said projection (12). An indicating apparatus as defined in claim 6, characterized in that said projection (12) is formed in a peripheral region of said take-up element (7). An indicating apparatus as defined in claim 6, characterized in that said bore (9b) is in form of a slot extending longitudinally of said pointer (9). An indicating apparatus as defined in claim 2, characterized in that as viewed in a direction perpendicular to said first axis, said pointer (9) includes a horizontal portion extending substantially horizontally from said second axis, and an intermediate portion sloping, generally downwardly of said bicycle, from said horizontal portion. An indicating apparatus as defined in claim 9, characterized in that said pointer (9) further includes a distal end portion extending substantially vertically of said bicycle, from said intermediate portion. An indicating apparatus as defined in claim 1, characterized in that said shift lever (4) has a home position, a first shift position and a second shift position. An indicating apparatus as defined in claim 11, characterized in that said home position lies between said first shift position and said second shift position. An indicating apparatus as defined in claim 12, characterized in that said shift lever (4) is biased toward said home position to return to said home position after each shifting operation. An indicating apparatus according to any of the preceding claims, characterized by a pointer (9) extending substantially parallel to said first axis and a connector disposed between a peripheral region of said take-up element (7) and said pointer (9) for causing said pointer (9) to pivot in response to rotation of said take-up element (7). An indicating apparatus as defined in claim 14, characterized in that said connector includes a projection fixedly formed on said take-up element (7) and a slot formed in said pointer (9) for receiving said projection.

Inventors: KAWAKAMI TATSUYA, KISHIMOTO HITOSHI, KAWAKAMI, TATSUYA, KISHIMOTO, HITOSHI
Applicants: SHIMANO KK, SHIMANO INC.
Application year: 1994
Main classification: B62M25
IPC codes: B62M25, B62K23